Preliminary Observations on Phagocytosis in the Peripheral Blood of Sockeye Salmon (Oncorhynchus nerka)

Abstract

The ability of circulating leucocytes of non-immunized, cultured sockeye salmon to phagocytize bacteria in the blood stream was examined using two techniques; cannulation of the dorsal aorta (for the injection of bacteria and for blood sampling) and intracardiac injection. With the first technique no phagocytosis was observed in the peripheral blood but there was a rapid uptake of bacteria that was particularly impressive in the kidney. Some phagocytosis in the blood stream, mostly by polymorphonuclear leucocytes, was demonstrated using the second technique but there was the possibility that these phagocytes had actually drained from the renal portal system following caudal blood sampling. The results so far confirm the observations of others that phagocytosis in the peripheral blood of salmonids is insignificant or non-existent.